The ATtiny85 module is a great option for running simple Arduino programs, it's small, cheap and relatively easy to use.
If your project requires only a few simple inputs or outputs, then this is an ideal module.
- support for the Arduino® IDE
- power via ubs or external Source (pinheader)
- onboard 5 V regulator
- built-in usb
- 6 I/O pins
- 8k flash memory (about 6k after bootloader)
- I2C and SPI
- PWM on 3 pins
- ADC on 4 pins
- power LED and LED on P1
- working voltage: 1.8 - 5.5 VDC
- dimensions: 17.5 x 19 mm